An Overview of the Options for Antimicrobial Hard Surfaces in Hospitals - Use of Biocidal Surfaces for Reduction of Healthcare Acquired Infections - page 141

lack of residual effect, meaning that recontamination occurs quickly [ 49 , 50 ].
Another problem is that a high proportion of surfaces in a room are missed during
cleaning and disinfection [ 51 ]. Antimicrobial surfaces (AMS) offer the potential
for providing a continuous reduction on microbes deposited on surfaces, which
provides a complimentary approach to improving hospital surface hygiene.
AMS have a potential role in supplementing, to an extent, deficiencies in conven-
tional cleaning and disinfection. AMS also have a potential role even when
conventional cleaning and disinfection is functioning perfectly, since surfaces
cannot feasibly be continuously cleaned and disinfected using standard methods.
AMS have a number of inherent limitations. Firstly, in general, contamination is
reduced but not eliminated by AMS. It would be possible to create a surface that
would eliminate pathogens on contact, but this surface would not be safe for human
contact. Continuous sub-lethal exposure of microbes to any antimicrobial agent is
likely to result in some level of microbial reduced susceptibility, which is therefore
a potential concern for all AMS. Also, it is not clear what level of environmental
contamination burden reduction is necessary to block transmission, as discussed
above. Secondly, it is not feasible to make all surfaces in a room antimicrobial
with most AMS technologies. Also, sometimes it may not be feasible to make
the highest-risk touch surfaces antimicrobial with some technologies. Thirdly,
the introduction of AMS will be associated with some cost, which requires
evidence-based justification. Fourth, the long-term durability of AMS in the busy
healthcare environment has not been established for many technologies. Finally,
there may be problems with patient and staff acceptability of AMS for some
technologies.
7.2 Current Options and the 'Ideal' Candidate
for Antimicrobial Surfaces
A number of review articles provide an overview of AMS [ 52 - 55 ], and others have
reviewed the literature related specifically to copper [ 56 , 57 ] or silver surfaces [ 58 ].
A number of these reviews have used the term 'self-disinfecting surfaces'.
This term suggests an active disinfection process, which does not properly capture
the continuous disinfection activity. Thus, I have used the term 'antimicrobial
surfaces' (AMS) throughout this review.
There are several approaches to making a hospital surface 'antimicrobial'
(Table 7.1 ):
￿ Permanently 'manufacture in' an agent with antimicrobial activity (e.g. copper
or a chemical).
￿ Periodically apply an agent with antimicrobial activity (e.g. copper containing
liquid agents, or chemical disinfectants with residual activity).
￿ Physically alter the properties of a surfaces to make it less able to support
microbial contamination and/or easier to clean (e.g. a coating that make a
surface 'superhydrophobic').